To calculate maths operation in a column using pandas

Question

I would like to use python to get final values for maths operation in a column of a CSV file, may I know is it possible to get the value as below?

Original CSV:

Type Total
A    2+2
B    (10/2)*5
C    5-2*3

Expected Output:

Type Total
A    4
B    25
C    -1

I have tried searching around but I could not get any idea on it... All data are in string, I tried to convert to float but due to the maths operation, so it cannot be done.

Answer 1

Use pandas.eval with Series.apply:

df['Total'] = df['Total'].apply(pd.eval)
print (df)
0    A    4.0
1    B   25.0
2    C   -1.0

Dont use:

df['Total'] = pd.eval(df['Total'])

because failed if more like 100 rows.

EDIT: If need working only for not missing values:

mask = df['Total'].notna()
df.loc[mask, 'Total'] = df.loc[mask, 'Total'].apply(pd.eval)

EDIT1: If possible some values which cannot be processed use custom function with try-except:

print (df)
  Type     Total
0    A       2+2
1    B  (10/2)*5
2    C     5-2*3
3    D       NaN
4    E       aaa

def func(x):
    try:
        return pd.eval(x)
    except:
        return x

df['Total'] = df['Total'].apply(func)
print (df)
  Type Total
0    A     4
1    B    25
2    C    -1
3    D   NaN
4    E   aaa